If u feel that strongly that u want to put it in words go through the neccesary chanells and put it in an increp or Airprox form.
All of these are extensively investigated by the powers that be and if it is as serious as you state Mr Barnard then corrective and disciplinary action will be taken against those resposible from an ATC point of view.
I will be the first to say I am far from perfect and make plenty stuff ups, I just try correct them before they become paperwork, but hey we all human dude and if we are working everyday we bound to make 1 or 2 misshaps in a shift. Most are correctable as are most misshaps that go on in a flight deck but if you feel it was a danger a mag is not the place to express this. Follow the laid out channels bro.